Pressure fluid servomotor and valve system therefor



Jar 15, 1952 c. F. TERWILLEGER 2,582,570

PRESSURE FLUID SERVOMOTOR AND VALVE SYSTEM THEREFOR 2 Sl-IEETS-SHEET l Filed Feb. 14, 1949 Jan- 15, 1952 cgF. TERWILLEGER 2,582,570

PRESSURE FLUID sEEvoMoToR AND VALVE SYSTEM THEREFOR Filed Feb. 14. 1949 2 SHEETS--SIIEET 2 A nventor;

Gttorneg rengine is to be made.

ward end of the cylinder, I provide solenoid valves 24 and 35. Valve 24 has a pipe connection 26 at one siderwith the pressure line 22, and a pipe connection 29 from its other sideinto thecylinder.V The valve 35, likewise,l has pipe connection 36 to the pressure line 22 and a connectionv and this has an atto valve 43, and there is a connection 59 from wire 59 to solenoid valve 35.

Each of the solenoids of the eight solenoid valves used has a ground connection'such as at -g in Fig. 3', withv a ground Vwire'lS.

The switch designated by reference character A comprises an insulated base block mounted on top of or fixed relative to cylinder I5. Slidconnection 34 at its other side, withV pipe 32.

When either valve 23 or 30 is opened, operating air will be admitted therethrough from pipe 22 able through the vblock is a rod 1| which is parallel with the axis of the cylinder I5 and at one vend is fixed by means of a bracket 12 to the piston rod I8 in such manner that rod 1| moves into .the forward end of the cylinder |5 as a f means for moving the piston rearwardly therein. When valve 33 is opened, air may be exhausted from the forward end of the cylinder `through pipes. 28, 32 and 34 and the valve 33.

Asolenoid exhaust valve 38V also is associated .with the valves 24 and 35. This has an opening to. atmosphere at one side and is connected at its other side by a pipe 39` with pipe 31 which opens into pipe 29. When valve 38 is open, air may be exhausted from the rearward end of the cylinder.

Associated with the central portion of the cylinder l5 are solenoid exhaust valves 42 and 43. Valve 43 has` an opening at one side to atmosphere and has pipe connection 44 at its other side leading into the cylinder I5 at a point n that isclosely adjacent the forward side of the piston;|1 when it is ina neutral position in the cylinder. Likewise, valve 42 has an opening to atmosphere at one side and at its other side has a pipe connection 45 opening into the cylinder at a position that will be closely adjacent the rearward side of the piston when it is ina neutral setting. The preferred arrangement of valves islas shown in Fig. 2, but they may be in other arrangement so long as their pipe connections Awith the cylinder. correspond to that shown and their functions are Vnot changed.

A'The valves may be alike in construction and their mod e of operation the same. The function of` each valve is to control the flow of air therethrough into or from the cylinder. Each valve comprises a casing containing a movable valve .element that is retained normally in a closed position by spring means or otherwise, and movable upon the energization of its. associated solenoid,to an;open position. Normally, all Yvalves are. closed and'selected valves are opened only when change in the operating position of the The wiring diagram for the controlV of the solenoids is shown in Fig. 3, wherein 58 designatesa source of electricalv energy with line 5|, leading therefrom, and provided with connections ,with each of three normally open switches designated at F, R and N, which, respectively, are closed to eiect the forward, reverse or neutralsetting of the engine by the mechanism. From theoutgoing Vside of switch R circuit wires 52 and 53 lead, respectively, to the solenoids of valves 23 and 38. From the outgoing side of switch F, circuit wires 54 and 55 lead, respectively, to the solenoids of valves 24 and 33. From the outgoing side of switch N, a circuit wire 56 leads to a control switch, presently described in detail but designated in Fig. 3 in its entirety by reference character A. From this latterswitch, a circuit wire 58 leads to valve 30 and there is a connection 58 from wire 58 to solenoid valve 42. ,A A

vmother circuit wire 59 leadsfrom switch A e'ndwise in theblock in accordance with travel ofthe piston in its cylinder. The rod 1| is longitudinally channeled in opposite sides, the channels extending in opposite `directionsfrom a short unchanneled portion designated by numeral 1|a in Fig. 2a.. The channels are designated, :respectively by Vnumerals 14 and 15,. When the power transmission devices of the engine are set in a neutral position, the piston I1 will be located in the neutral position in cylinder I5, and the unchanneled part 1Ia: of the rod 1| will assume the position in block 10` as vshown in Fig. 4.

Fixed on the block 18 atone end and at opposite sides of 'position'of the,rod.1|,`are conltacts 16 and 11 to which wires'16' and 11', lead- Ving from wire 56, are connected.

Also mounted on Vthe block for slight swinging movement on pivot studs 18 and 19,"respectively. are switch arms and 8|; designed to make and break circuit connection at their swinging ends with the contacts 16 and 11, respectively. The circuit wires-58 and 59 previously mentioned lead respectively from the studs 18 and 19. Thus whenever arm 80 or arm l8| lengages with the corresponding contacts 16 and 11, a circuit will be closed through the switch arm, pivot stud and wire 58 -or 59 to energize the solenoid valves connected therewith.

-The switch arms 89 and 8| are spring pressed toward their circuit closing positions and are caused to move to open or closed positions in accordance with the longitudinal movements of rod 1I, this being accomplished through the following means: Y

Mounted in the block 10 at opposite sides of the rod 1|l are spring arms 84- and 85; each of which is flxedlyy mounted at one endl-to extend along the rod and atapoint vbetween its ends to press thereagainst. From their points of contact with the rod l1|, thespring armsl are turned outwardly, and at their ends carryv upwardly extending pins 84'-85fthat pass-'through slots in the top wall of thefhollow block 10 to engage. respectively, with the switch arms 80 and 8| for their actuation. Y

Switches R, N and F may be of the push-button type, or of any other type .that is normally open and'must bev pushedto closed position and ope when pressure is removed.

Assuming the parts tov be so constructedv and assembled, and that Ythe drive is set for forward operation .and that allwaves are closed. when the piston I1 is at the'forward end of the cylinder I5, as in Fig. 5, the'rodll will-then be disposed at that position atrwhich the switch arm 80 is permitted to engage contact 16 and switch arm 8| is caused to. be disengaged from contact 1|. l. f

Now should it be desired to shift the drive from forwardf to ."reverse operation, the operatormomentarily-.closes switch R.. An electric circuitis .thereby closed through the actuating solenoids of valves 23 and 38, the valves are thereby opened and pressure medium from pipe 22 is admitted to the cylinder to shift the piston Vi rearwardly and pull lever Il to reverse position. Likewise, to shift from reverse to forward operation, the switch F is momentarily held closed. This results in the opening of valves 24 and 33 and the admittance of pressure medium to the rearward end of the cylinder to effect the shifting of the piston l1 to the forward end of the cylinder l5.

When the rod 'Il is in its neutral position, the arms 84 and B5 engage with the unchanneled portion Hx thereof in such manner as to cause them to hold their corresponding switch arms 8i! and 6l disengaged from the contacts 16 and l1. When rod 'H is moved in one direction from neutral, the spring 84 under tension drops into the channel 'i4 and thus is moved away from the switch arm 88 and the latter makes a circuit connection with contact 16. Likewise, if the rod 'il moves in the other direction, the arm 85 drops into channel l5 and permits arm 8| to engage contact H to close a circuit connection.

When it is desired to shift from forward setting to neutraL switch N is momentarily closed. When the parts are in forward setting, the arm 80 and contact'l are engaged; thus when switch N is closed, a circuit is completed through valves and 42. Thus. pressure medium is admitted through valve 30 to drive the piston l? back to neutral position, as pressure medium at the other side of the piston is exhausted through valve 42. As the piston I1 reaches neutral, the rod 'Il moves to its neutral position, as in Fig. 4, and thus the switch arm 80 is disengaged from contact 16. This opening of the circuit permits both valves 30 and 42 to close, and the piston checked and held at neutral setting.

Likewise, if the drive is in reverse setting and it is desired to set it at neutraL the switch N is pressed closed. At this time the switch arm 8| will be engaged with contact 11, thus closing switch N. This causes circuits to be closed -f through valves and 43 and the pressure medium from pipe 22 admitted through valve 35 to drive the piston I1 to neutral setting. As lt reaches this position, rod 1| causes the arm 8| to be disengaged from contact 11 and the circuit therethrough to be opened, to close the valves 35 and 43 thus to hold the neutral setting.

If it is desired to shift from neutral to forward, or from neutral to reversef the switches F and R are used in the same manner as for shifting from reverse to forward, or from4 forward to reverse, and the same valves are energized as for these operations. The switch A 1s used only in connection with the changing of the drive from forward or reverse to neutral.

This device provides a practical, effective and easily controlled mechanical means for accomplishing what is rather difficult to do by hand, and makes possible the control of the engine from a remote location.

Having thus described my invention, what I claim as new therein and desire to secure by Letters Patent is:

l. A servo-motor for shifting the control lever or the power transmission mechanism of an engine to position at opposite sides of a neutral setting for forward or reverse driving; said servomotor comprising a pressure cylinder, a piston reciprocally movable therein and a rod connecting said piston with the said lever for its actua tion, a source of duid pressure medium, a irs and a second connection from said source or pressure medium into each of the opposite ends of the cylinder, a normally closed valve in connection, -a normally closed pressure exhaust valve for each of the opposite ends of the cylirm der, pressure exhaust valves opening from cylinder adjacent opposite sides of the neutral position of the piston therein, individuati solenoids for the valves adapted when energized to move their respective valves to open position, electric circuits for the various solenoids, contro? switches connected with said circuits and sel tively operable each to close circuits for open a valve in one of said first connections to a' it pressure medium to the corresponding end of c cylinder and to open the exhaust valve serving the other end of the cylinder, and other switches selectively operable, each to close the circuit for opening a valve in one rof said second connections and to simuitanccusly open the opposite neutral position exhaust valve.

2. A combination as recited in claim i including also a switch connected with said circuits and operable under control of movement of said piston from either end of the cylinder to a neutral position to open the then energized circuits.

3. A servo-motor for shifting the control lever of the power transmission mechanism of an engine to positions at opposite sides of a neutral setting for forward or reverse driving, said motor comprising a pressure cylinder, a piston movabie therein, a piston rod extended from the cylinder connection with the control lever for its actuation between opposite limits of travel by movement of the piston between opposite limits of travel, a source of fluid pressure medium, a rst and a second connection from said source of pressure medium into each of the opposite ends of the cyl inder, a normally closed valve in each connection, a normally closed pressure exhaust valve for each of the opposite ends of the cylinder, pressure exhaust valves opening from the cylinder adjacent opposite sides of the neutral position of the piston therein, individual soienoids for the valves adapted when energized to move their respective valves to open position, electric circuits for the various solenoids, a reverse switch operable to close circuits to solenoids that admit medium to the forward end of the cylinder and exhaust medium from the rearward end, a forward switch operable to energize solenods 'to admit pressure medium to the rear end of the cylinder and exhaust it from the forward end, a neutral switch operable to energize circuits whereby the medium is admitted through a second connection to move the piston to a neutral position from forward or reverse position, and an automatic switch operable under control of the piston movement to open the energized circuit when the piston reaches a neutral position.

CLARENCE F. TERWILLEGER.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,841,629 Pigeolet Jan. 19, 1932 2,156,118 Kliesrath Apr. 25, 1939 2,221,365 Ware Nov. 12, 1940 2,234,019 Bragg Mar. 4, 1941 2,314,444 Crittenden Mar. 23, 1943 2,375,946 Reichelt May 15, 1945 

